There are several things that can cause a No Heat situation. First - is the HEAT indicator light coming on? If it is -coming on- and you have no heat then we need to test for voltage at the heater wire terminals.

If the light is not ON -then something is not allowing the heater circuit to activate. First-- check the filter --is it clean? check the water level- is it Up where it should be?

The first thing to check is - if your pump is moving water properly. Do the jets seem to be the same pressure as they always have and are they moving water like normal?

If yes -we can assume the pump is still working well enough to make the system function. Most spas use a pressure switch as a safety switch --it senses pressure in the pipe and allows the heater to come On if pressure is present, but if no or low pressure is present then it will not allow the heater to operate. So... we need to make sure the pressure switch is operating. For most spas the spa will need to be running and the heat set where it would normally be --all we need to do is bypass the switch ( only long enough to see if the heater light will come on).

We can either jump across the two terminals on top of the switch-(where the two small wires connect) bridge the two terminals with a small screw driver or a jumper wire. On most newer spas with Balboa, brand or Gecko brand control boxes these two wires are low voltage control wires and not 120v power leads.

Well that depends ... how does your pressure switch look? is it leaking at all, or rusted? If not you may be able to adjust it. Look just below the switch on top were the wires connect-there should be a small wheel looking piece with a small plunger that pops up and activates the micro switch on top of the unit. That wheel can be turned to adjust the PSI setting for activation. In your case you would turn the wheel counter clockwise which should raise the plunger area to be closer to the switch on top. You just dont want to go to far -if you do the heater could stay on even once the pump has shut down. Give it a turn or two - then turn the power back on and see if it goes into the heat mode on its own.

On the other hand if the switch looks to be leaking at all or rusted --just replace it . Go to hottubworks.com and take a look. Most adjustable switches use a 1/8th pipe thread mount and use two wire terminals -- there are several with these specs and price can be very different depending on the manufacturer so if you have any doubt -- call or e-mail .